limestone in coral reefs

In Minecraft, Coral is growing on rock. In real life, coral grows on a specific kind of rock called limestone! You can find the stuff on coral, and when mined, can be crafted into smooth limestone, limestone stairs, chiseled limestone, limestone bricks, limestone slabs, and things to that nature. Coral giant stone boulders just seem off, and limestone can help add some realism, and more building block opportunities!